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Vanishing of the James brace product before rationalization for two classes of fibrations

Determine whether the James brace product { , }_s vanishes identically in the original (non-rationalized) fibration in each of the following settings: (i) an S^n-bundle S^n ↪ E → X with a homotopy section s, where X is simply connected and n > 1 is odd; and (ii) an S^k-bundle S^k ↪ E → G with a homotopy section s, where G is a simply connected compact Lie group and k > 1. Concretely, ascertain whether {α, β}_s = 0 for all α ∈ π_i(X) and β ∈ π_j(S^n) in case (i), and for all α ∈ π_i(G) and β ∈ π_j(S^k) in case (ii), without passing to rationalization.

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Background

In Section 5 the authors analyze rationalized fibrations and show that, in certain classes, the James brace product vanishes after rationalization. Specifically, they consider (i) the rationalized fibration of any Sn-bundle over a simply connected space X with a section, for n > 1 odd, and (ii) the rationalized fibration of any Sk-bundle over a simply connected compact Lie group G with a section, for k > 1. In both situations they demonstrate vanishing of the brace product in the rationalized setting.

However, they explicitly note that they do not know whether this vanishing extends to the original (non-rationalized) fibrations. The open problem asks for a determination of whether the James brace product vanishes identically at the fibration level itself in these two classes, i.e., without invoking rationalization.

References

In the above two examples, we do not know whether the James brace product vanishes at the fibration level itself (before taking the rationalization).

On the James brace product: Generalization, relation to $H$-splitting of loop space fibrations & the $J$-homomorphism (2401.16206 - Basu et al., 29 Jan 2024) in Section 5 (Localization of Spaces and Brace Product)